Ultra-wideband 1bit reconfigurable reflectarray based on tight coupling method

The paper utilizes the tightly coupled antenna design method to introduce the tightly coupled form into the design of the reconfigurable reflectarray element, and realizes an ultra-wideband 1bit reconfigurable reflectarray element. The method of the tightly coupled antenna is to connect adjacent elements together. And the adjacent reflectarray elements are connected together, which can expand the bandwidth. The form of tight coupled is achieved by the comb-strip which is used to connect the adjacent reflectarray elements. The tightly coupled reconfigurable reflectarray element is composed of two rectangular patches and two comb-shaped strips. One of the rectangular patches is divided into two patches by the groove, and a PIN diode is loaded on the groove. The opened and closed of the PIN diode can achieve two states with a phase difference of 180°. In addition, the period of the reconfigurable reflectarray element in the polarization direction is one-third of the wavelength, which is also the reason for increasing the bandwidth. The simulation results show that the bandwidth of the 1bit reconfigurable reflectarray element with a difference of 180°±20° between the two-phase states is 8GHz-12.5GHz, and the relative bandwidth is 43%. An 1bit reconfigurable reflectarray is designed with 18×12 elements, and the bandwidth of the array is 40%.